The objectives of this grant are: to establish the usefulness of tissue DHT concentrations in prostate cancer tissue for the prediction of the occurrence and duration of clinical response to hormonal or ablative therapy in advanced prostate cancer. This will be supplemented by attempting to establish biochemical parameters to identify the nonhormone dependent clone present in prostate cancer by measuring PAP/DHT ratios, which appear to be a potential marker for such clones. A possible relationship between tissue grading alone or combined with biochemical parameters to further help in the prediction of clinical response to hormonal therapy will also be studied. A possible role for adrenal cortical androgens in producing relapse in hormone treated patients will be assessed by the simultaneous measurement of plasma testosterone levels and tissue DHT levels at the time of relapse. The prediction of the long term outlook in patients with less advanced disease who are radiated will also be studied by electron and light microscopy, tissue culture techniques and measurement of DHT concentrations 1 to 1 1/2 years following radiation therapy.